Treatment of Neurodegenerative Diseases

ABSTRACT

The present specification discloses beta-amino alcohols and methods of treating a neurodegenerative disease using such compounds.

PRIORITY CLAIM

This application is a continuation that claims priority pursuant to 35 U.S.C. 120 to U.S. Non-Provisional patent application Ser. No. 12/066,904, filed Sep. 8, 2008, a national stage entry of PCT/GB2006/003529, filed Sep. 21, 2006, which claims priority to Great Britain Patent Application No. 0519274.5, filed Sep. 21, 2005, each of which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Field of the Invention

This invention relates to the treatment of neurodegenerative diseases.

2. Background of the Invention

Neurodegenerative diseases are conditions that affect brain or peripheral nerve function. They result from the deterioration of neurons and they are characterised by progressive central or peripheral nervous dysfunction. They are divided into two groups: conditions causing problems with movement or sensation and conditions affecting memory or related to dementia. Neurodegenerative diseases include: Alexander disease, Alper's disease, Alzheimer's disease, amyotrophic lateral sclerosis, ataxia telangiectasia, Canavan disease, Cockayne syndrome, corticobasal degeneration, Creutzfeldt-Jakob disease, Huntington disease, Kennedy's disease, Krabbe disease, Lewy body dementia, Machado-Joseph disease, multiple sclerosis, Parkinson's disease, Pelizaeus-Merzbacher disease, Pick's disease, primary lateral sclerosis, Refsum's disease, Sandhoff disease, Schilder's disease, Steele-Richardson-Olszewski disease, tabes dorsalis and Guillain-Barre Syndrome. Currently there are no effective cures for these conditions, and very few treatments are available.

SUMMARY OF THE INVENTION

Surprisingly, it has been found that beta-amino alcohols are useful for the treatment of neurodegenerative diseases. The beta-amino alcohols are of formula (I)

wherein R₁ is CHR₄—OR₅ or CHR₄—SR₅, or aryl or heteroaryl optionally substituted with one or more groups R₆; R₂ is alkyl or is part of a ring with R₃; R₃ is H, alkyl or CH₂ (when forming part of a ring with R₂); R₄ is H or alkyl or is part of a ring with R₅; R₅ is aryl or heteroaryl optionally substituted with R₇; each R₆ is independently alkyl, CF₃, OH, Oalkyl, OCOalkyl, CONH₂, CN, halogen, NH₂, NO₂, NHCHO, NHCONH_(2l , NHSO) ₂alkyl, CONH₂, SOMe, SO₂NH₂, Salkyl, CH₂SO₂alkyl or OCONalkyl₂; R₇ is R₈ or (CH₂)_(n)OR₈, R₉, CF₃, OH, OR₉, OCOR₉, COR₉, COOR₉, CONH₂, CH₂CONH₂, CN, halogen, NH₂, NO₂, NHCHO, NHCONH₂, NHCONHR₇, NHCON(R₉)₂, NHCOR₉, NHCOaryl, NHSO₂Me, CONH₂, SMe, SOMe or SO₂NH₂; R₈ is (CH₂)_(n)OR₉, (CH)_(n)OR₉, (CH₂)_(n)COOR₉ or (CH₂)_(n)COaryl; R₉ is alkyl or cycloalkyl; and n is 1 to 4; or a salt thereof.

DESCRIPTION OF THE DRAWING

FIG. 1 is a graph showing the effects of (+)-erythro-2-tert-butylamino-1-(3-chlorophenyl)propan-1-ol hydrochloride (Example 1) and Copaxone on neurological scores induced in a model.

DESCRIPTION OF THE INVENTION

It is understood that the invention refers to salts, e.g. the hydrochloride, metabolites and pro-drugs thereof, as well as any diastereomers and enantiomers of (I).

Some of the compounds of formula (I) have antihypertensive, vasodilator, sympathomimetic, bronchodilator or cardiostimulant activity through agonism and antagonism at alpha and beta adrenoceptors. These agents have at least one chiral centre and their activity at the alpha or beta adrenoceptors resides mainly or solely in one of the enantiomers. If the molecule has more than one chiral centre, the activity at the alpha or beta adrenoceptors resides mainly in one of the diastereomers.

The preferred diastereomer or enantiomer of (I) has little or no activity at the α or β adrenoceptors. This activity may be determined by use of the appropriate in vitro assay.

The compounds of formula (I) according to the invention are useful to treat neurodegenerative diseases including Alexander disease, Alper's disease, Alzheimer's disease, amyotrophic lateral sclerosis, ataxia telangiectasia, Canavan disease, Cockayne syndrome, corticobasal degeneration, Creutzfeldt-Jakob disease, Huntington disease, Kennedy's disease, Krabbe disease, Lewy body dementia, Machado-Joseph disease, multiple sclerosis, Parkinson's disease, Pelizaeus-Merzbacher disease, Pick's disease, primary lateral sclerosis, Refsum's disease, Sandhoff disease, Schilder's disease, Steele-Richardson-Olszewski disease, tabes dorsalis or Guillain-Barre Syndrome.

Compounds of formula (I) may be used according to the invention alone, in combination with another therapeutic agent, or in treatment of a patient also being administered another therapeutic agent. Such other agents include cholinesterase inhibitors (examples including galantamine, rivastigmine, donepezil, tacrine), steroids, interferons and glutamate receptor agents such as AMPA, kainate agents and NMDA antagonists (examples including memantine).

Any suitable route of administration can be used. For example, any of oral, topical, parenteral, intracerebroventricular, spinal, ocular, rectal, vaginal, inhalation, buccal, sublingual and intranasal delivery routes may be suitable. The dose of the active agent will depend on the nature and degree of the condition, the age and condition of the patient and other factors known to those skilled in the art. A typical dose is 0.1-100 mg given one to three times per day.

The following Example illustrates the invention.

EXAMPLE

Experimental Allergic Encephalomyelitis (EAE) is a central nervous system, autoimmune, demyleinating disease, that mimics many aspects of multiple sclerosis. Acute models of murine EAE are often utilised to evaluate the efficacy of therapeutics.

Method

Acclimatised SJL mice were sensitised by a subcutaneous injection proteolipid protein (PLP) in Freund's complete adjuvant (CFA) acting as an encephalitogenic inoculum. Innoculum was administered subcutaneously at a concentration of 125 μg PLP/300 μg CFA in a volume of 200 μl. 48 hours later, an intraperitoneal injection of pertussis toxin (PTX) was administered at a dose of 20 μg/kg, to increase blood-brain barrier permeability.

(+)-Erythro-2-tert-butylamino-1-(3-chlorophenyl)-propan-1-ol hydrochloride and copoxane were administered from the first day of the experiment and once a day until the end. (+)-Erythro-2-tert-butylamino-1-(3-chlorophenyl)-propan-1-ol hydrochloride was administered orally at a dose of 10 mg/kg. Copaxone was administered intraperitoneally at a dose of 25 mg/kg. Throughout the experiment, careful clinical examinations and body weights were taken to observe the well being of the animal. In addition, clinical scoring of the EAE symptoms was taken to the classical 0-5 scale, as follows:

-   -   0 Normal reactions     -   1 Tail weakness     -   2 Hind leg weakness and paresis     -   3 Hind leg paralysis     -   4 Quadriplegia     -   5 Moribund/death

Results

FIG. 1 describes the effect of orally administered (+)-erythro-2-tert-butylamino-1-(3-chlorophenyl)-propan-1-ol hydrochloride (10 mg/kg) and intraperitoneally administered Copaxone (25 mg/kg) versus the vehicle control (for (+)-erythro-2-tert-butylamino-1-(3-chlorophenyl)-propan-1-ol hydrochloride) on SJL mouse EAE neurological scores.

EAE-induced mice exhibited pronounced neurological deficits as defined by the vehicle group. Weaknesses in hind limb were recorded by day 10 and peaked at day 17 with a maximum neurological deficits score of 2; which relates to deficits in walking and unsteady gait.

(+)-Erythro-2-tert-butylamino-1-(3-chlorophenyl)-propan-1-ol hydrochloride showed no improvement in the maximal neurologic score, but exhibited a more rapid improvement in symptoms, accelerating disease resolution compared to the vehicle.

Copaxone delayed the onset of neurological symptoms by 2-3 days, but had no effect on the improvement of symptoms, seemingly worsening this aspect of the model.

These data show that (+)-erythro-2-tert-butylamino-1-(3-chlorophenyl)-propan-1-ol hydrochloride has a quantifiable effect on the SJL EAE model of multiple sclerosis, and suggesting that this molecule is a potential treatment for multiple sclerosis. 

1. A method of treating a neurodegenerative condition, the method comprising the step of administering to an individual in need thereof a compound of formula (I)

wherein R₁ is CHR₄—OR₅ or CHR₄—SR₅, or aryl or heteroaryl optionally substituted with one or more groups R₆; R₂ is alkyl or is part of a ring with R₃; R₃ is H, alkyl or CH₂ (when forming part of a ring with R₂); R₄ is H or alkyl or is part of a ring with R₅; R₅ is aryl or heteroaryl optionally substituted with R₇; each R₆ is independently alkyl, CF₃, OH, Oalkyl, OCOalkyl, CONH₂, CN, halogen, NH₂, NO₂, NHCHO, NHCONH₂, NHSO₂alkyl, CONH₂, SOMe, SO₂NH₂, Salkyl, CH₂SO₂alkyl or OCONalkyl₂; R₇ is R₈ or (CH₂)_(n)OR₈, R₉, CF₃, OH, OR₉, OCOR₉, COR₉, COOR₉, CONH₂, CH₂CONH₂, CN, halogen, NH₂, NO₂, NHCHO, NHCONH₂, NHCONHR₇, NHCON(R₉)₂, NHCOR₉, NHCOaryl, NHSO₂Me, CONH₂, SMe, SOMe or SO₂NH₂; R₈ is (CH₂)_(n)OR₉, (CH)_(n)OR₉, (CH₂)_(n)COOR₉ or (CH₂)_(n)COaryl; R₉ is alkyl or cycloalkyl; and n is 1 to 4; or a salt thereof.
 2. The method according to claim 1, wherein the neurodegenerative condition is a multiple sclerosis.
 3. The method according to claim 1, wherein the neurodegenerative condition is an Alzheimer's disease.
 4. The method according to claim 1, wherein the neurodegenerative condition is a Parkinson's disease.
 5. The method according to claim 1, wherein the compound is chiral and is an enantiomer or a diastereomer.
 6. The method according to claim 1, wherein the compound has relatively little or no activity at an α adrenoceptor or a β adrenoceptor.
 7. The method according to claim 1, wherein the individual is also administered an additional therapeutic agent, the additional therapeutic agent includes a cholinesterase inhibitor, a steroid, an interferon, or a glutamate receptor agent.
 8. The method according to claim 7, wherein the glutamate receptor agent is an AMPA, a kappa agonist, or a NMDA agonist.
 9. The method according to claim 7, wherein the compound and the additional therapeutic agent are provided in combination.
 10. The method according to claim 1, wherein R₁ is aryl substituted by CF or halogen, R₂ is alkyl, and R₃ is H or alkyl.
 11. The method of claim 1, wherein the compound is (+)-erythro-2-tertbutylamino-1-(3-chlorophenyl)-propan-1-ol. 